Final answer:
The noun 'water' in the sentence 'The students drank all the water in the pitcher' cannot be counted as it is an uncountable noun.
Step-by-step explanation:
In the sentence, 'The students drank all the water in the pitcher,' the noun 'water' is the one that names something that cannot be counted. It is an uncountable noun because it refers to a substance that cannot be easily divided into separate, countable units. Examples of other uncountable nouns include 'milk,' 'air,' and 'sugar.'